Cytoskeletal F-actin patterns in skin fibroblasts from normal subjects and patients with tuberous sclerosis and von Recklinghausen's neurofibromatosis.

Abstract

Cytoskeletal F-actin of formaldehide fixed, acetone-extracted cells was stained with 7-nitrobenz-2-oxa-1,3-diazole(NBD)-phallacidin. Skin fibroblasts from apparently normal fetuses, children and adults, and from patients with tuberous sclerosis (TS) (6 strains) and von Recklinghausen's neurofibromatosis (NF) (4 strains) were examined. Skin fibroblasts from patients with adenomatosis of the colon and rectum (ACR) and basal cell naevus syndrome (BCN) and simian virus 40 (SV40) transformed skin fibroblasts were also included. About 75% of the SV40 transformed cells had less or no organized actin fibers, as repeatedly reported for many virally transformed cell systems. In rapidly proliferating cultures of fibroblasts from normal subjects, highly organized action fibers were seen in 74.8 and 77.3% of the cells from fetal and child cell cultures, respectively, and in 84.0% of cells from adult cell cultures at the same low levels ofin vitro passage (p<0.001). This suggests that the organization of actin fibers increases with age and that the change is similar to that duringin vitro senescence. In fibroblasts from patients with TS and NF, the organization of actin fibers was almost the same as that of normal fibroblasts.